UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from_______________ to _______________ Commission File Number: 001-39103 CABALETTA BIO, INC. (Exact Name of Registrant as Specified in its Charter) Delaware (State o ...

Cabaletta Bio° Corporate Presentation MARCH 2022 © 2022 Cabaletta Bio. All rights reserved. Disclaimer 2 The following presentation, including any printed or electronic copy of these slides, the talks given by the presenters, the information communicated during any delivery of the presentation and any question and answer session and any document or material distributed at or in connection with the presentation (collectively, the "Presentation") has been prepared by Cabaletta Bio, Inc. ("we," "us," "our," "C ...

Cabaletta Bio° Corporate Presentation MARCH 2022 © 2022 Cabaletta Bio. All rights reserved. Disclaimer 2 The following presentation, including any printed or electronic copy of these slides, the talks given by the presenters, the information communicated during any delivery of the presentation and any question and answer session and any document or material distributed at or in connection with the presentation (collectively, the "Presentation") has been prepared by Cabaletta Bio, Inc. ("we," "us," "our," "C ...

Part I [Financial Statements (Unaudited)](index=3&type=section&id=Item%201.%20Financial%20Statements%20%28Unaudited%29) The unaudited financial statements present Cabaletta Bio's financial position as of September 30, 2021, showing a net loss of **$32.4 million** for the first nine months of 2021 and increased cash and equivalents due to stock offerings [Condensed Balance Sheets](index=6&type=section&id=Condensed%20Balance%20Sheets) As of September 30, 2021, total assets increased to **$122.6 million**, driven by a rise in cash and cash equivalents to **$118.3 million**, while total stockholders' equity grew to **$116.6 million** Condensed Balance Sheet Data (in thousands) | Account | Sep 30, 2021 (Unaudited) | Dec 31, 2020 | | :--- | :--- | :--- | | **Assets** | | | | Cash and cash equivalents | $118,260 | $101,429 | | Total current assets | $120,852 | $113,535 | | **Total Assets** | **$122,638** | **$114,724** | | **Liabilities & Equity** | | | | Total current liabilities | $6,023 | $5,180 | | Accumulated deficit | ($98,699) | ($66,298) | | Total stockholders' equity | $116,615 | $109,544 | | **Total Liabilities and Stockholders' Equity** | **$122,638** | **$114,724** | [Condensed Statements of Operations and Comprehensive Loss](index=7&type=section&id=Condensed%20Statements%20of%20Operations%20and%20Comprehensive%20Loss) For the nine months ended September 30, 2021, the company reported a net loss of **$32.4 million**, primarily due to increased Research and Development costs of **$22.6 million** and General and Administrative expenses of **$9.8 million** Statement of Operations Highlights (in thousands) | Metric | Nine Months Ended Sep 30, 2021 | Nine Months Ended Sep 30, 2020 | | :--- | :--- | :--- | | Research and development | $22,575 | $15,601 | | General and administrative | $9,845 | $8,902 | | **Total operating expenses** | **$32,420** | **$24,503** | | Loss from operations | ($32,420) | ($24,503) | | **Net loss** | **($32,401)** | **($24,030)** | | Net loss per share | ($1.31) | ($1.09) | [Condensed Statements of Stockholders' Equity](index=8&type=section&id=Condensed%20Statements%20of%20Stockholders%27%20Equity) Total stockholders' equity increased to **$116.6 million** as of September 30, 2021, driven by common stock issuances that offset the **$32.4 million** net loss incurred - For the nine months ended September 30, 2021, the company issued common stock raising net proceeds of **$34.7 million** through its **ATM program** and an additional **$0.5 million** from stock option exercises[31](index=31&type=chunk)[82](index=82&type=chunk) - The accumulated deficit increased from **$66.3 million** at the end of 2020 to **$98.7 million** by September 30, 2021, due to ongoing net losses[31](index=31&type=chunk) [Condensed Statements of Cash Flows](index=10&type=section&id=Condensed%20Statements%20of%20Cash%20Flows) For the nine months ended September 30, 2021, net cash used in operating activities was **$23.6 million**, while financing activities provided **$35.3 million**, resulting in a net increase in cash and cash equivalents of **$16.8 million** Cash Flow Summary (in thousands) | Activity | Nine Months Ended Sep 30, 2021 | Nine Months Ended Sep 30, 2020 | | :--- | :--- | :--- | | Net cash used in operating activities | ($23,594) | ($17,597) | | Net cash provided by (used in) investing activities | $5,150 | ($9,872) | | Net cash provided by (used in) financing activities | $35,275 | ($56) | | **Net increase (decrease) in cash** | **$16,831** | **($27,525)** | | Cash and cash equivalents—end of period | $118,260 | $108,679 | [Notes to Unaudited Condensed Financial Statements](index=11&type=section&id=Notes%20to%20Unaudited%20Condensed%20Financial%20Statements) The notes detail Cabaletta Bio's clinical-stage focus on engineered T cell therapies, its high dependence on the **University of Pennsylvania (Penn)** for research and manufacturing, and its financial commitments and liquidity projections - The company is a clinical-stage biotechnology firm focused on developing engineered T cell therapies for B cell-mediated autoimmune diseases. It is highly dependent on the **University of Pennsylvania (Penn)** for preclinical research, clinical development, and initial manufacturing activities[36](index=36&type=chunk)[39](index=39&type=chunk) - Management expects that cash and cash equivalents of **$119.3 million** as of September 30, 2021, will be sufficient to fund operations for at least **12 months** from the filing date[41](index=41&type=chunk)[42](index=42&type=chunk) - The company has a sales agreement for an "**at-the-market**" (**ATM**) offering of up to **$75.0 million**. During the nine months ended September 30, 2021, it sold **3,606,005** shares for net proceeds of **$34.7 million**[82](index=82&type=chunk) - The company has committed to funding a research plan with **Penn** through February 2023 with a total estimated cost of **$12.3 million**, of which **$9.3 million** has been incurred as of September 30, 2021[67](index=67&type=chunk)[108](index=108&type=chunk) [Management's Discussion and Analysis of Financial Condition and Results of Operations](index=20&type=section&id=Item%202.%20Management%27s%20Discussion%20and%20Analysis%20of%20Financial%20Condition%20and%20Results%20of%20Operations) Management discusses the company's focus on developing CAAR T cell therapies, its increased net loss of **$32.4 million** for the nine months ended September 30, 2021, driven by higher R&D expenses, and its liquidity supported by equity offerings [Overview](index=24&type=section&id=Overview) **Cabaletta Bio** is a clinical-stage biotech developing engineered T cell therapies for autoimmune diseases, with its lead candidate **DSG3-CAART** in a Phase 1 trial and **$119.3 million** in cash and investments as of September 30, 2021 - The company's lead product candidate, **DSG3-CAART**, is being evaluated in the Phase 1 **DesCAARTes™** trial for mucosal pemphigus vulgaris (mPV)[102](index=102&type=chunk) - The lead preclinical candidate, for **MuSK myasthenia gravis** (**MuSK MG**), is in IND-enabling studies with an IND submission planned for Q4 2021[102](index=102&type=chunk) - As of September 30, 2021, the company had **$119.3 million** in cash, cash equivalents, and investments, funded primarily by its **IPO** and **at-the-market** offerings[102](index=102&type=chunk) [Results of Operations](index=30&type=section&id=Results%20of%20Operations) Operating expenses increased for the nine months ended September 30, 2021, with R&D expenses rising by **$7.0 million** to **$22.6 million** and G&A expenses by **$0.9 million** to **$9.8 million**, leading to a net loss of **$32.4 million** Comparison of Operating Expenses for the Nine Months Ended September 30 (in thousands) | Expense Category | 2021 | 2020 | Change | | :--- | :--- | :--- | :--- | | Research and development | $22,575 | $15,601 | $6,974 | | General and administrative | $9,845 | $8,902 | $943 | | **Total operating expenses** | **$32,420** | **$24,503** | **$7,917** | - The **$7.0 million** increase in R&D expenses for the nine months ended Sep 30, 2021, was primarily driven by a **$2.8 million** increase in development services, a **$1.7 million** increase in personnel costs, and a **$1.5 million** increase in clinical trial costs for the **DesCAARTes™** trial[130](index=130&type=chunk) [Liquidity and Capital Resources](index=33&type=section&id=Liquidity%20and%20Capital%20Resources) The company holds **$119.3 million** in cash, equivalents, and investments as of September 30, 2021, sufficient to fund operations through at least Q1 2023, but anticipates continued losses requiring substantial additional financing - As of September 30, 2021, the company had **$119.3 million** in cash, cash equivalents, and investments and an accumulated deficit of **$98.7 million**[134](index=134&type=chunk)[135](index=135&type=chunk) - The company believes its existing cash will fund operating expenses and capital requirements through at least the first quarter of 2023[137](index=137&type=chunk) - Through its **ATM Program**, the company sold **3,606,005** shares for net proceeds of **$34.7 million** during the nine months ended September 30, 2021, and an additional **600,000** shares for **$6.3 million** subsequent to the quarter-end[138](index=138&type=chunk) [Quantitative and Qualitative Disclosures About Market Risk](index=29&type=section&id=Item%203.%20Quantitative%20and%20Qualitative%20Disclosures%20About%20Market%20Risk) The company's primary market risk is interest rate sensitivity on its **$119.3 million** in cash and investments, but a **1%** change in rates is not expected to have a material effect due to their short-term, low-risk nature - The company's primary market risk is interest rate sensitivity on its **$119.3 million** of cash, cash equivalents, and investments[156](index=156&type=chunk) - Due to the short-term and low-risk nature of its investments, a **1%** change in interest rates is not expected to have a material effect on fair market value[156](index=156&type=chunk) - The company does not have any foreign currency or derivative financial instruments[157](index=157&type=chunk) [Controls and Procedures](index=29&type=section&id=Item%204.%20Controls%20and%20Procedures) Management concluded that the company's disclosure controls and procedures were effective as of September 30, 2021, with no material changes to internal control over financial reporting during the quarter - Management concluded that as of September 30, 2021, the company's disclosure controls and procedures were effective at a reasonable assurance level[158](index=158&type=chunk) - There were no changes in internal control over financial reporting during the quarter that materially affected, or are reasonably likely to materially affect, internal controls[159](index=159&type=chunk) Part II [Legal Proceedings](index=30&type=section&id=Item%201.%20Legal%20Proceedings) As of September 30, 2021, the company is not involved in any material litigation or legal proceedings expected to have a material adverse impact on its financial position - The company is not currently involved in any material legal proceedings[162](index=162&type=chunk) [Risk Factors](index=30&type=section&id=Item%201A.%20Risk%20Factors) The company faces significant risks including its early development stage, dependence on **DSG3-CAART** and the **University of Pennsylvania**, a history of losses requiring substantial funding, and complexities in manufacturing and intellectual property - The company is an early-stage clinical company with a limited operating history, dependent on the success of its initial product candidates, particularly **DSG3-CAART**[6](index=6&type=chunk)[164](index=164&type=chunk)[185](index=185&type=chunk) - The company is highly dependent on its relationship with the **University of Pennsylvania (Penn)** for preclinical R&D, technology, and clinical trial manufacturing[7](index=7&type=chunk)[331](index=331&type=chunk) - The company has incurred significant losses since inception and will need to raise substantial additional funding to complete development of its product candidates[6](index=6&type=chunk)[9](index=9&type=chunk)[257](index=257&type=chunk) - Manufacturing of the company's CAAR T cell product candidates is complex, novel, and susceptible to technical and logistical failures, with reliance on a limited number of third-party suppliers for key components like viral vectors[14](index=14&type=chunk)[360](index=360&type=chunk)[369](index=369&type=chunk) [Unregistered Sales of Equity Securities and Use of Proceeds](index=91&type=section&id=Item%202.%20Unregistered%20Sales%20of%20Equity%20Securities%20and%20Use%20of%20Proceeds) The company reported no unregistered sales of equity securities during the period - There were no unregistered sales of equity securities in the reported period[506](index=506&type=chunk) [Defaults Upon Senior Securities](index=91&type=section&id=Item%203.%20Defaults%20Upon%20Senior%20Securities) The company reported no defaults upon senior securities - There were no defaults upon senior securities[506](index=506&type=chunk) [Mine Safety Disclosures](index=91&type=section&id=Item%204.%20Mine%20Safety%20Disclosures) This item is not applicable to the company - Not applicable[506](index=506&type=chunk) [Other Information](index=91&type=section&id=Item%205.%20Other%20Information) The company reported no other information for this period - None[507](index=507&type=chunk) [Exhibits](index=92&type=section&id=Item%206.%20Exhibits) This section lists the exhibits filed with the quarterly report, including amendments to key agreements with the **University of Pennsylvania** and officer certifications - Filed exhibits include amendments to key agreements with the **University of Pennsylvania** and the Children's Hospital of Philadelphia, as well as required CEO and CFO certifications[510](index=510&type=chunk)

Cabaletta Bio° Corporate Presentation SEPTEMBER 2021 © 2021 Cabaletta Bio. All rights reserved. Disclaimer 2 The following presentation, including any printed or electronic copy of these slides, the talks given by the presenters, the information communicated during any delivery of the presentation and any question and answer session and any document or material distributed at or in connection with the presentation (collectively, the "Presentation") has been prepared by Cabaletta Bio, Inc. ("we," "us," "our, ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2021 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from_______________ to _______________ Commission File Number: 001-39103 CABALETTA BIO, INC. (Exact Name of Registrant as Specified in its Charter) Delaware (State or ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2021 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from_______________ to _______________ Commission File Number: 001-39103 CABALETTA BIO, INC. (Exact Name of Registrant as Specified in its Charter) Delaware (State o ...

Cabaletta Bio° Corporate Presentation APRIL 2021 © 2021 Cabaletta Bio. All rights reserved. Disclaimer 2 The following presentation, including any printed or electronic copy of these slides, the talks given by the presenters, the information communicated during any delivery of the presentation and any question and answer session and any document or material distributed at or in connection with the presentation (collectively, the "Presentation") has been prepared by Cabaletta Bio, Inc. ("we," "us," "our," "C ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-39103 82-1685768 (I.R.S.Employer Identification No.) CABALETTA BIO, INC. (Exact name of Registrant as specified in its Charter) Delaw ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from_______________ to _______________ Commission File Number: 001-39103 CABALETTA BIO, INC. (Exact Name of Registrant as Specified in its Charter) Delaware (Sta ...